A time domain winner-take-all network of integrate-and-fire neurons

A time domain winner-take-all circuit based on simple self-resetting integrate-and-fire neurons is presented in this paper. Integrate-and-Fire (I&F) neurons can translate the intensity of a current input into a time domain signal: Strong input current will lead to an early spike output and weak input to a late output. By making the self-reset line global for all neurons, only the first spiking neuron, which is the neuron with the strongest input, will ever spike, and thus, win over the others. This WTA circuit was conceived as part of an imager chip to process current input from a motion detection array, thus detecting the row and column of maximum change of illumination. The fact that this WTA processes analog input and produces spike output is most convenient for the address event interface (AER) that conveys the WTA output off-chip. We verified the WTA functionality with experiments of an AMS 0.6mum CMOS implementation. Some suggestions on how to achieve additional functions by simple extensions of the circuit are discussed.